The document discusses coordination and response in living organisms. It describes how stimuli are detected by receptors and transmitted via sensory neurons to the central nervous system for integration. The CNS then sends signals to effectors like muscles and glands via motor neurons to elicit a response. This ensures coordinated functioning of the organism as a whole. The nervous and endocrine systems facilitate coordination and response through electrical and chemical signaling respectively.

1. COORDINATION AND
RESPONSE

2. • Living organisms have the ability to detect
the internal and external environment
changes

3. The changes which cause response in the body
are called stimuli

4. • Two types of stimuli:
• (a) internal stimuli
• Changes in blood pressure, sugar level

5. • (b) external stimuli
– Changes in light intensity, sound, temperature,
pressure, touch

6. Stimuli receptors Effector
Response

7. • A response is the ways an organisms react after
stimulus is detected
Stimuli receptors Effector
Response

8. When stimuli are detected and eventually result
in reponse it is called coordination
Stimuli receptors Effector
Response

9. • Coordination ensures the activities of an
organism function as an intergrated whole

10. Coordination and
response
Nervous system Endocrine system

12. Nervous system
Sensory
receptors
Intergrating
centre
effectors

13. Peripheral
Nervous system
efector
Central nervous
system

14. • Sensory receptors
– Detect changes in the external environment
• Found in eyes, nose, ears, tongue, skin

15. - Detect changes in the internal environment
Located in specific internal organs

16. • Examples of external environment receptors:
– Light sensitive cell in the retina
– Temperature and touch receptor in the skin
– Vibration sensitive cells in the ears

17. • Examples of internal environment
receptors :
–Cells sensitive to level of carbon dioxide in the
blood, blood osmotic pressure

18. Pancreatic cells detect blood glucose level

19. • Intergrating centre
– Intergrating centre is the central nervous system
( brain, spinal cord)

20. Intergration happens when information from the
receptors is interpreted to bring appropriate
response

21. • Effectors
– Carry out the responses to stimuli
– Effectors – muscle cells, glands

22. Sensory receptor is
stimulated , nerve
impules are
generated
Impulse carried along
the afferent pathway through
the afferent nerves
Impulses arrive at the
intergrating centre
Integration centre sent
response in the
impulse form
Impulses is carried by
efferent pathway through the
efferent nerves to effectors
Reponse to the
stimuli take place

24. Pathway involved in detecting and responding to
change in the internal environment
Change in the
blood temperature
Detected by temperature
sensitive cells in hypothalamus
Impulses are carried by
afferent nerves to the
thermoregulatory centre
in hypothalamus
Integration occur in
thermoregulatory centre
Impulses are carried
from hypthalamus
to the effector through
efferent nerves
Effectors – smooth
mucles of the arterioles,
sweat gland, etc

25. Change in the blood temperature

26. Detected by temperature
sensitive cells in hypothalamus

27. Impulses are carried by afferent nerves to the
thermoregulatory centre in hypothalamus

29. The role of the human nervous
system

30. Human nervous system
Central nervous
system
Peripheral nervous
system
brain Spinal cord Cranial
nerves
spinal
nerves

31. Cranial nerves are nerves that emerge directly
from the brain, in contrast to spinal nerves
which emerge from segments of the spinal
cord

32. • Nervous system performs three main functions :
– 1. sensory
– 2. intergrative
– 3. motor

33. • sensory receptors detect stimuli – initiate
impulses that carry information to the CNS

34. • CNS – initiate suitable responses
• Motor commands from the CNS are transmitted
to the effectors - muscles, glands

35. • Human brain :
– Cerebrum
– Cerebellum
– Medulla oblongata
– Thalamus
– Hypothalamus

36. Cerebral cortex

37. Cerebrum
- largest, most complex part of the brain
- divided into two – left hemisphere
- right hemisphere

38. • Left hemisphere – controls movements on the
right side of the body

39. Functions – receive the sensory input and
carries out integrative functions before
initiating motor response

40. – Coordinates the activities other parts of the brain

41. • Outer region of the cerebrum - cerebral cortex
– Many folds to increase surface area
Cerebral
cortex

42. – Function –
• directs voluntary muscle movement, result in sensory
perception (know what he sees, hears, smell)

43. Mental abilities – learning, memorising,
reasoning, language skills, mathematic skills,
imagination, artistic talents, personality

44. • Damage to this area can cause specific defect –
speech impairment, reading difficulty, paralyse

45. • Cerebellum
– The coordinating centre for body movements
– Receieves information from sensory receptor from
all parts of the body and from the cerebrum

46. – Evaluate infromation and relays the need for
coordinated movements back to the cerebrum
– Cerebrum then sends appropriate commands to the
muscles

47. • Medulla oblongata
– Function –
• regulates the internal body processes that do not require
conscious effort – heartbeat, breathing, vasoconstriction

48. • Reflex centre for vomiting, coughing, sneezing,
hiccupping, swallowing

49. • Hypothalamus
– Function – homeostatic regulation
– Coordintion centre for regulating sleep, hunger,
thirst, body temperature, water balance, blood
presure

50. – Control centre for endocrine system (hormone)

51. • Pituitary gland
– Function – secretes hormones that influence other
glands and body functions

52. The hypothalamus controls the release of
several hormone from the pituitary gland

53. • Thalamus
– Function –
• sorting the incoming and outgoing information in the
cerebral cortex
• Enhancing and blocking signals from the sensory
receptors to the cerebrum

54. The spinal cords and it functions
• Spinal cord is surrounded by cerebrospinal fluid
-shock absorber and provide nutrients
• Consist of white matter and grey matter

58. Dorsal root
ganglion

59. • Spinal nerves emerge from the spinal cord
through two branches/ roots:
• Dorsal roots
• Ventral roots
Dorsal root

60. • Dorsal roots
– Contains axon of the afferent neurons which conduct
nerve impulses from the sensory receptors to the
spinal cord

61. Dorsal root
ganglion

62. – Dorsal root ganglion contains the cell bodies of
afferent neurons

64. • Ventral root
– Contains the axons of the efferent neurons which
conduct impulses away from the spinal cord to the
effector

65. Dorsal root
ganglion

67. • The spinal cord :
– Processes sensory information and send out
responses through the efferent neurones

68. – Contains neurones that transfer signals to and from
the brain
– Neural pathway for reflexes

69. receptor Neuron afferent Spinal cord
brain
Neuron efferent
Effectors
/muscle
Pathway off the impulse

70. The neurones
• The nervous system is made up of millions of
nerve cells calls neurones
• Neurones transmit nerve impulses to other
nerve cells, glands, muscles

73. • Three types of neurones:
• Afferent neurones
• Efferent neurones
• internuerones

74. • Afferent neurones
– Carry sensory information from the receptor cells to
the brain and spinal cord

75. Movement of impulse

76. • Efferent neurones
– Carry information from the brain or spinal cord to the
effectors (muscle, gland cells)

77. Movement of impulse

78. • Interneurones
– Convey nerve impulses between various parts
of the brain and spinal cord
– Transmit nerve impulses between afferent
neurones and efferent neurones
– Transmit nerve impulses from one side of the
spinal cord to the other side or from brain to
the spinal cord

80. The transmission pathway of information

82. Receptors pick up
the ringing of
doorbell
Nerve impulses
from the
receptors moves
in the afferent
neruones
Nerve impulses
transfer from the
afferent to the
interneurons
Interneurones
sent impulses
to the brain
Brain interpretes
impulses, give order
in the form of
impulses
From the
interneurones
impulses is
transmitted to
the efferent
neurones and then
to the muscles
The muscles in the
arm carry out response

83. The transmission of information along
the neurones
• The transmission of information along the
neurones is through electical signals known as
nerve impulses

84. • Impulse – positive charges that travel along the
axon to the synaptic terminal

85. • A neurones will not transmit impulses if the
stimulation is not strong enough

86. Afferent neurones interneurones Efferent neurones
impulse impulse
Receptor
Brain
impulse
Stimulus
impulse
Interpret, Integration,
Response

87. Receptors pick up
the ringing of
doorbell
Nerve impulses
from the
receptors moves
in the afferent
neruones
Nerve impulses
transfer from the
afferent to the
interneurons
Interneurones
sent impulses
to the brain
Brain interpretes
impulses, give order
in the form of
impulses
From the
interneurones
impulses is
transmitted to
the efferent
neurones and then
to the muscles
The muscles in the
arm carry out response

88. The transmission of information
across synapses
• Neurones are not connected to each other

89. • Beyond the synaptic terminal there is synaptic
cleft (narrow space) that separate synaptic
terminal from the dendrite of a receiving
neurones
Synaptic cleft
Synaptic terminal
dendrite

92. • Synapse is the site where two neurones or a
neurone and an effector cell communicate

93. • Electrical signals must be transmitted across the
synaptic cleft to an adjacent cell

94. • The transmission of nerve impulses across the
synaptic cleft occurs with the help of
neurotransmitter (chemical substances)

96. • Neurotransmitter is stored in the synaptic
vesicles

97. • The transmission of impulses involves the
conversion of electrical signal into chemical
signals

98. Electrical
signal
Chemical
signal
Electrical
signal
(neurotransmitter)

99. Electrical impulses
reaches the presynaptic
membrane
Neurotransmitter diffuse
across the synaptic cleft
and bind to specific
protein/receptors
that attached to the
postsynaptic membrane
Binding of the
neurotransmitter to
receptors
generates a new impulses
signal
Impulses is transferred
to another neurones

100. • The transmission of nerve impulses across
synapses is an active process which required
energy

101. • Synaptic terminal contains abundant
mitochondria to generate energy for
transmission of nerve impulses

102. • After the neurotransmitter has relayed its
message
– Broken down by enzymes
– Taken up again by the synaptic terminal and
recycled

104. • Examples of neurotransmitter :
• Acetylcholine
• Noradrenaline
• Serotonin
• dopamine

105. • The functions of synapses :
• Controlling and intergrating the nerve impulses

106. • Facilitating the transmission of nerve impulses in one
direction
– Synaptic vesicles only present in synaptic terminals

107. – Only presynaptic membrane can discharge neurotransmitter
– Receptors only present in postsynaptic membranes

109. Action of skeletal muscle
Voluntary action Involuntary action

110. • Voluntary action of the skeleton muscle
– Voluntary actions are under conscious control

111. – Information that reaches cerebral cortex or
conscious level result in a perception of the
external environment

112. Stimulus receptor Afferent
neurone
Cerebral
cortex
Efferent
neurone
effector
response

113. • Involuntary action that involves the skeletal
muscles: the reflex arc
– Involves skeletal muscle that does not require
consciuos effort

114. • Example – if a finger touch a hot stove, the
reactions is to pull the finger away without
having to thing

115. • Rapid, automatic
• The nerve pathway involved is called reflex arc

116. Reflex arc
Sharp pin pierces
the skin – sensory receptor
in the skin generate
nerve impulses
Nerve impulses transmitted
along an afferent neurone
toward the spinal cord
In spinal cord the
nerve impulses are
transmitted to the
interneurone
From interneurone the
impulses are transmitted
to the efferent neurone
Efferent neurone
carries the nerve
impulses to the
effector
Pin can be pulled
out immediately

117. The importance of reflexes
- Cut the time of response

118. - the pain is slightly delayed after the response
has been made

119. • Only involves the spinal cord, the brain is
reserved for more complex task

120. • Reflex that involves the brain
– The opening and closing of the pupil of the eye
– Automatic response, we have no control of the size
of the pupil

121. • Another types of automatic response is knee
jerk reflex
– Involves afferent neuron and efferent neurone

122. Knee jerk response
Rubber hammer
hits a tendon that
connect the
quadriceps muscle
in the thigh to a
bone in the lower
leg
The force stretches
the quadriceps muscles
and stimulate the
stretch receptors in
the muscles, triggering
nerve impulses
Afferent neurones transmit
impulses to the efferent
neurones in the spinal
cord
The efferent neurones
transmit impulses to
the quadriceps muscle,
muscle contract, the leg
jerking forward

124. Reflex arc
Afferent neurones -
interneurones – efferent
neurones – effector
-- piercing of the skin
Afferen neurone – efferent neurone
-
effector
-
--knee jerk reflect
Afferent neurones – brain
- interneurone – efferent
neurone – effector
--opening and closing of
the pupil

126. Involuntary action which involves smooth
muscles, cardiac muscle or glands
1. The autonomic nervous system
- controls involuntary actions involving :

127. * glands
*cardiac muscle
* smooth muscle of the internal organs

128. – Connects the medula oblongata and hypothalamus
with the internal organs and regulates the internal
body processes
– Require no conscious effort
Cerebral
cortex

129. – Impulses are not transfered to the cerebral cortex –
we were not aware of the response

130. – Enable vital functions – heartbeats, blood
circulation – continues during unconsciousness /
sleeping

131. – Autonomic nervous system can be divided into :
• Sympathetic division
• Parasympathetic division

133. Sympathetic division
- prepares the body for stressful situations
- increase the pulse rate, blood pressure,
breathing rate
-

134. slows down the digestive system – more blood is
available to carry oxygen to vital organs (heart,
brain)

135. Parasympathetic division
- prepares the body during ordinary situations /
relaxed state
-

136. decrease the pulse rate, blood pressure,
breathing rate
-stimulate the digestive system to continue
breaking down food

137. Diseases of the nervous system
1. Parkinson's disease
- affect the muscular movements causing tremors
or trembling of the arms, jaws, leg, face
- difficulty maintaining normal postures, impaired
balance and coordination

138. 2. Alzheimer's disease
- neurological disorder causes the loss of
reasoning and ability to care fo oneself
- individuals becomes confuse, forgetful, lose
ability to read, write, eat, walk and talk

139. • The information for involuntary actions does not
involve the cerebral cortex
– No perception is generated
– We not aware of the response

140. The role of Hormones in humans
• Hormones are chemical messengers produced
by the endocrine gland

141. • Endocrine glands – ductless glands that
release hormones directly into the interstitial
fluid and then to the bloodstream

142. • Hormones only affect specific target cell
• Hormones causes the target cell to respond in a
specific manner

143. The need for the endocrine
system
• The endocrine and nervous system play
important roles in maintaining homeostasis
• Some physiological processes need both
system too work together, others only involve
the endocrine system

144. The nervous system
controls voluntary
and involuntary actions
conveys impulses
message conducted
via neurones
message are carried
between specific
location
responses or effects
are temporary
message are conveyed
rapidly
The endocrine system
controls involuntary
actions
conveys chemical signals
message are conveyed
via bloodstream
message are carried to
various destinations
responses or effects
are long lasting
message are conveyed
slowly

145. The human endocrine system
- consist of glands that contain hormones-
secreting cells
- the glands secrete different types of hormones
involved in specific physiological processes

146. Function of hormones
Reproduction
Follicle stimulating
hormone, luteinising
hormone, oestrogen,
progesterone, androgen
Growth
Growth hormone,
thyroid stimulating
hormone, thyroxine
Homeostasis
Insulin, glucagon,
antidiuretic,
adrenaline

147. Endocrine gland
Anterior pituitary
gland
Posterior pituitary
gland
Thyroid stimulating
hormone (TSH)
follicle stimulating
hormone (FSH)
luteinising hormone (LH)
adrenocorticotrophic hormone
growth hormone (GH)
Prolactin (PRL)
Antidiuretic hormone
(ADH)
Oxytoxin

149. Other endocrine glands
• Thyroid gland
– Thyroxine

150. • Adrenal cortex
– Aldosterone

151. • Pancreas
– Insulin
– Glucagon

152. • Ovaries
– Oestrogen
– Progesterone

153. • Testis
– Testosterone

154. Regulation of hormone secretion
- endocrine gland release hormones more
frequently when stimulated
-

155. • hormone secretion is normally regulated to
prevent over production or under production

156. • Regulation of hormone is controlled by:
• Signals from nervous system
• Other hormones
• The level of specific substances in the body

157. The regulation of hormone secretion by signal
from the nervous system
- pituitary gland is the master of endocrine gland
because it secreters hormones that control
other endocrine gland

158. • The pituitary gland is controlled by
hypothalamus
• Posterior pituitary gland contains axons and
synaptic terminals of the neurosecretory cells
that originate in the hypothalamus

159. • Hypothalamus :
• Controlling the secretion of hormones from the pituitary
gland
• Link between the nervous system and the endocrine
system

160. • Maintain homeostasis by receiving impulses of the
internal environment
• Have specialised nerve cells called neurosecretory

161. Neurosecretory cells
in hypothalamus
ADH, oxytoxin
pass through the
axon into the
posterior pituitary
cells and stored in
the synaptic terminals
ADH and oxytoxin
are secreted into
the bloodstream
Hypothalamic releasing
hormones, hypothalamic
inhibiting hormones
These hormones are
carried in the blood
stream to the anterior
pituitary
Hypothalamic releasing
hormones stimulate the
seretion of anterior pituitary
hormones
Hypothalamic inhibiting
hormones prevent the secretion
of the anterior pituitary
hormones

162. hypothalamus
Hypothalamic releasing
hormones
Hypothalamic inhibiting
hormones
Anterior pituitary
Secretion of anterior
Pituitary hormones
Inhibition of secretion of
Anterior pituitary hormones
ADH and oxytoxin
Posterior pituitary
gland
ADH , oxytoxin
Secreted into the
Blood stream

163. The regulation of hormone secretion by other
hormones

164. hypothalamus
Thyroid releasing hormones
Anterior pituitary gland
Thyroid stimulating hormones
Thyroid gland
Thyroxine hormones
Are released

165. • The secretion of most hormones is first
regulated and controlled by the nervous system

166. • Hormones that are released by the pituitary
gland are used to stimulate other glands to
secrete hormones

167. Posterior
pituitary
Anterior
pituitary
ADH
- kidney
tubule
Oxytoxin
- smooth muscle
in the uterus
ACTH
-adrenal
cortex
TSH
- thyroid
FSH, LH
- ovaries,
testes
GROWTH
HORMONE
- bone, tissues
PROLACTIN
- mammary
glands
Pituitary

168. • The release of a hormone from the target exerts
a negative feedback control

169. Thyroid releasing
hormone from
hypothalamus TRH stimulate the
anterior pituitary
to secrete TSH
TSH stimulates the
thyroid gland to
secrete thyroxineWhen thyroxine
concentration is high,
its inhibit TRH production
from the hypothalamus
and TSH from the anterior
pituitary

170. The regulation of hormone secretion by the level
of specific substances in the blood
- the secretion of hormones is regulated by the
level of specific substances in the blood

171. • Examples :
• Blood glucose level rises, the pancreas
produces insulin

172. • Insulin increase the glucose uptake by the cell
• Cells metabolise or convert the glucose to
glycogen

173. • The blood glucose level returns to normal

174. The involvement of the nervous and
endocrine system in a fight or flight
situation

175. Fight or flight situation
Nerve impulses from the
hypothalamus stimulate the
neurones from the sympathetic
division of the autonomic nervous
system in the adrenal medulla
Stimulate the adrenal
medulla to secrete
adrenaline and
noradrenaline
Adrenaline and
noradrenaline cause an
increase in heartbeat,
breathing rates, blood
pressure, blood glucose
level, metabolic activity

176. Fight or flight situations
Nerve impulses from hypothalamus
Stimulates the neurones from the symphathethic
Division of the autonomic nervous system in the adrenal
medulla
Stimulate the cells of the adrenal medulla to secrete
Adrenaline and noradrenaline
Adrenaline and noradrenaline cause increase in heartbeat,
Blood pressure, blood glucose level, metabolic activity

177. • The hearts contracts vigorously to pump larger
amount of oxygen and glucose to the brain and
skeletal

178. • Skeletal muscle becomes more energised and
enable a person to fight or flee immediately
from danger

179. • The nervous and endocrine system working
together to bring immediate response to cope
with threat

180. Hormon imbalance and related disease
1. growth hormone
- over secretion
– gigantism
- acromegally (adult) – bones, hand, feet, cheek
& other tissues enlarge

183. - under secretion :
- dwarfism
- genetically enginered growth hormone is given
to the children allowing them to attain normal
height

184. 2. Thyroxine
- over secretion :
- increase metabolic rate – excessive sweating,
heat intolerence, nervousness, rapid heart rate,
weight loss

185. - goitre – thyroid gland enlarge – iodine
deficiency
- thyroid gland cannot synthesise enough
thyroxine, its enlarge in response from
pituitary gland

186. – Under secretion :
• Child - Severe mental retardation (cretinism)
• Adult – myxedema – slow heart rate, low body
temperature, sensitive to cold, gain weight easily

187. 3. Insulin
- Over secretion – hypoglecaemia (low level
of glucose in the body)

188. - symptoms – fatigue, insomnia, mental
confusion, nervousness, mood swings, fainting
spells, headaches

189. – Under secretion – diabetes mellitus
• Abnormally high level of glucose in the blood
• Body do not produce enough insulin or cannot use the
insulin that are produced

190. • Increase frequency of urination
• Large quantities are produced by genetically engineered
bacteria – injected to the patient

191. 4. ADH
- Over secretion
- high retention of water in the body

192. – Under secretion
• Diabetes insipidus
• Excrete a large amount of urine
• Always thirsty, drinks frequently
• Water lost in the urine

193. Homeostasis in humans
• The maintainance of relatively constant internal
environment is known a homeostasis

194. • Internal environment consist of phyical factors
and chemical factors

195. The excretory system
• Primary organs – kidneys
– Regulate water and salt balance – excreting more or
les salt, increasing intake or loss of water

196. – Regulate osmotic pressure and ionic level in the
bloods
– Excrete waste products
– Regulate blood pH

197. Waste products
From metabolic reactions
- urea, creatinine
(from amino acids)
- uric acids (from nucleic acids)
Foreign substances in
the diet
- drugs, toxin

198. The human kidney
• Kidneys filter blood and form urine
• Urine exits thorugh the ureter, urinary
bladder and urethra

199. • Urine consist of :
• Water
• Urea
• Disolved waste
• Exces nutrients

200. • Kidney has two region :
• Renal cortex – outer light red region
• Renal medulla – inner dark red region

202. The nephron
- the funcional unit of a kidney
- each kidney – about one million nephrons
-

204. - consists of three major parts :
1. glomerulus and its blood vessels
2. Bowman's capsule
3. renal tube

206. • Renal tube is made up of :
• Proximal convoluted tubule
• Loop of Henle
• Distal convoluted tubule

207. • Three basic processes to produce urine:
• Ultrafiltration
• Reabsorption
• Secretion

208. Ultrafiltration in Bowman's capule
- podocytes and endothelium of the the
glomerulus form a filtration membrane
-

209. permits the passage of water and solute from the
blood into the capsular space

210. • Blood pressure is high when it reach the
nephron

211. • The pressure increase because the afferent
arteriole has larger diameter than the efferent
arteriole

212. • Blood enters the glomerulus
– Ultrafiltration take place
– High pressure forces fluid through the filtration
membrane into the capsular space

213. – Filtration membrane filter certain size of molecules
– Fluid that pass the filtration membrane is called
glomerulus filtrate

214. • Glomerulus contents :
• Water, glucose, amino acids, urea, mineral salts, small
molecule
• Same composition as blood plasma
• No red blood cells, plasma proteins (too large)

215. Afferent
arteriole
Glomerulus
Efferent
arteriole
Efferent arteriole
divides into blood capillaries
surrounding kidney tubules
Blood capillaries -
Peritubular capillaries
Blood capillaries join
together to form renal
vein

216. Reabsorption
- take place when substances move across the
walls of the renal tubule into the capillary
network
-

217. - Chloride ions move out passively
- reabsorption of glucose and amino acids through
active transport
-

218. - movement of solutes into the capillary network
increase the concentration solute in the
capillary network
- water moves into the blood capillaries by
osmosis

219. - Loop of Henle:
- water, sodium, chloride ions are reabsorbed

220. - Distal convoluted tubule :
- watery filtrate contains low in salt, high in waste (
urea)
- more water, sodium, chloride ions are
reabsorbed

221. - Collecting duct :
- filtrate has very little salt, 99% of water has been
reabsorbed
- only 1 % of the water leaves as urine
-

222. urine moves down the collecting duct
- some urine diffuse out into surrounding fluid
and blood ( small size )
-

223. 45% of the original urea remain to be excreted
as urine

224. Secretion
- there are waste products in the blood that were
not filtered
-

225. secretion is a process in which waste and
excess substances that were not initially
filtered are secreted into the renal tube

226. - Secretion at – renal tubule, collecting ducts,
distal convoluted tubule
-

227. - occurs by active and passive transport
-

228. secreted substances :
– Hydrogen ions
– Potassium ions (K+)
– Urea
– Creatinine
– Toxin
– drugs

229. • Positive feedback mechanism produces a
response that intensifies the original change

230. • Example :
– The release of the oxytoxin which stimulates and
intensifies uterine contraction during labour

231. - by adjusting the amount of ions to reabsorb or
secretion, the kidneys can regulate chemical
composition of the blood

232. The constituents of urine
- pH – slightly acidic
- Water – 1-2 litres
- Uric acid - 0.8g
- Cl- - 6.3g
- Creatinine – 1.6 g

233. - Na+ - 4 g
- HCO3- - 0.03 g
- Urea – 30 g
- K + - 2 g

234. Negative feedback mechanism

235. • Internal environment of the human body must
be maintain at constant level

236. • Internal environment :
– Tissue fluid
– Blood
– lymph

238. • Factors affecting internal environment:
• Blood sugar level
• Body temperature
• Blood osmotic pressure
• Partial pressure of oxygen and carbon dioxide

239. Blood sugar level
Body temperature
Blood osmotic pressure
Partial pressure of oxygen
and carbon dioxide

240. • The maintenance of relatively constant internal
environment - Homeostasis

241. • Homeostasis is achieved by negative feedback
mechanism

242. • Whenever changes occur in internal
environment our body will initiates a corrective
mechanism

243. Normal
value
Value rise Corrective
mechanism
Normal value
Corrective
mechanism
Value drops
Negative feedback
Negative
feedback
Blood
pressure

244. • Kidney involves in negative feedback
mechanism to maintain homeostasis

245. The role of kidneys in Homeostasis
- the body gains and loss water every day

246. • Kidney control the water content of the blood at
constant level
– osmoregulation

247. Osmoregulation – the process of maintaining
the water content of the blood at constant
level

248. Homeostasis achieved by regulating the
volume of urine production and excretion

249. Drinks too
much water
Blood osmotic
pressure drops
below normal
Osmoreceptor cells
in hypothalamus are
less stimulated
Pituitary glands
less stimulated
Less ADH is
secreted from pituitary
glands
Low level of ADH
cause the distal tubule
& collecting duct less permeable
to water
Less water is
reabsorbed into the
blood
The result – increase
the blood osmotic pressure
and return to normal

250. Low level of ADH
cause the distal tubule
& collecting duct less permeable
to water
Less water is
reabsorbed into the
blood

251. Drinks too
little
Blood osmotic
pressure increases
above normal
Osmoreceptor cells
in the hypothalamus
detect increase in
blood osmotic
pressure
Osmoreceptor cells
in the hypothalamus
stimulate pituitary
gland to release more ADH
ADH increases
the permeability of the
distal tubule and
collecting duct
More water is reabsorbed
from the filtrate into the
blood
Blood pressure return
to normal
Water content of the
urine decreases.
Urine more concentrated , dark

252. ADH increases
the permeability of the
distal tubule and
collecting duct
More water is reabsorbed
from the filtrate into the
blood

253. • The lower osmotic pressure reduces the activity
of the hypothalamic osmoreceptor cells

254. • Osmoreceptor cells stop stimulating pituitary
gland to secrete more ADH

256. Kidney Problem
- kidneys of some people are damaged due to
diseases , drug or injury

257. Treatment
- Haemodialysis
- kidney transplants

258. haemodialysis – the process of filtering blood by
using an artificial means that replace the
functions of a failed kidney

259. – Blood from the artery is passed through the machine
which contains a dialyser
– Dialyser has two sections separated by semi
permeable membrane

260. – Blood passes on one side of the membrane and
dialysis solution passes on the other

262. – The different concentration gradient between the
blood and dialysis solution is such that the waste
molecules and excess salts can diffuse through the
membrane

263. Blood Dialysis
solution
Toxin from the blood diffuse
through the semi permeable
membrane
Required ions and
glucose are added
into the dialysis
solutin
Semi permeable membrane

264. • Another treatment for impaired kidney is the
transplant of a healthy kidney from a donor to
the patient

265. The regulation of blood sugar level
- pancreas gland is responsible for maintaining
the blood sugar level within 75-110mg/100ml

266. - pancreas secrete insulin hormone and
glucagons into the bloodstream

267. Insulin and glucagons

268. High blood sugar
concentration
Low blood sugar
concentration

269. • Insulin reduce the blood glucose level
• Glucagon increase the the blood glucose level

270. • Both hormone work in opposition to regulate
the blood glucose level

271. • Diabetes mellitus
– Defects in production, release, and reception of
insulin
– The proximal convoluted tubule cannot reabsorb all
the glucose from the kidney filtrate

272. The regulation of body temperature
- the body temperature fluctuate
- maintains at 37 C

273. Changes in the
external temp.
Cause initial
change in body
temp.
Changes detected by
Thermoreceptors in
hypothalamus
detect blood temp.
Thermoreceptors in
the skin detect external
temperature
Thermoregulatory centre
in the hypothalamus
Smooth muscles
in the arterioles
Sweat gland Erector muscles
in the skin
Skeletal
muscles
Adrenal,
thyroid glands

275. Internal temp.
rises, vasodilation occurs
when smooth muscles around
afferent arteriole relax
Increase blood
flows through the
skin
Increase the amount
of heat radiated and loss
by the skin
Temperature rises

276. Internal temp. rises
Sweat glands secrete
sweat to the surface
of the skin and evaporate
The body cools
and the internal
temperature drops
to set point once
again
The temperature
drop beneath set point
sweating stop, body heat
conserved

277. Internal temperature
rises above the set
point
Erector muscles
in the skill relax
lowering the skin
hair, warm air is not
trapped
Internal temperature
drops below the
set point, erector muscle
contract, raising the skin
hairs, trapping layer of warm air

278. Internal temperature
rise above set point
Skeletal muscle are
not stimulated,shivering
does not occur
Internal temperature
drops beneath set
point
Skeletal muscles
are stimulated, shivering
occurs

279. Internal temperature
rise above the set point
Adrenal and thyroid
glands are less stimulated
to secrete adrenaline and
thyroxine
The metabolic rate
is low, no excess heat
is generated
Internal temperature
drops beneath below
the set point
Adrenal and thyroid
glands are stimulated
to secrete more adrenaline
and thyroxine
Metabloc rate increase,
more heat is generated

280. Practising a healthy lifestyle
• Drugs can alter brain functions and the rates at
which neurones releases neurotransmitter

281. • The abuse of drugs reuslt in a tolerance of the
drug
• More and more drugs is needed to get the same
initial effect on the person

282. • Types of drugs:
• Stimulants
• Depressants
• Hallucinogens
• Narcotics

283. • Stimulants
– Increase activity of the central nervous system
– Blocks the removal of pleasure -inducing
neurotransmitters
– e.g. - cocaine

284. • Depressants
– Slow down the activity of the central nervous system
– Slow down the transmission of nerve impulses
– e.g : alcohol
– Inhibits the release of ADH
– Large volumes of urine

285. • Hallucinogens
– LSD (D-lysergic acid diethylamide)
– See, hear and percieve things that do not exist

286. • Narcotics
– Feeling euphoria, block pain signals, slow down
normal brain function
– e.g.: heroine, morphine
– Mimick neurotransmitter binding to their receptor
sites

287. Plant Hormones
• Types of plant hormones :
– Auxins
– ethylene

288. • Plant produce hormones for growth and
development

289. Auxins
- promote cell elongation cell lengthening
- produced in apical meristem at the tip of the
shoots
- result – increase the stem length by increasing
the rate of cell division

291. • The role of auxins in phototropism:
– Growth of plants towards light is caused by unequal
distribution of auxins in the shoot

292. ..........
...........
Even distribution
of auxin
Sunlight from
all side

293. • When a plant is exposed to light from one
direction
• Auxin build up on the side in the shade, and
stimulate the growth of the side that do not
receive sunlight

294. • The side that do not receive sunlight divide
faster and elongate faster than the side that
receive sunlight
• Result – the shoot bending towards the lights
• Auxin result in positive phototropism in plant
shoots

295. The role of auxin in geotropism
- if the seeds is buried horizontally
- light and gravity causes the auxins to be
transported to the lower side of the root or shoot
-

296. • The auxin that accumulate at the lower side of
the shoot stimulate the elongation of the shoot
• Result – the shoot bends upwards

297. • The auxin that accumulate at the lower side of
the root inhibits the elongation of the root
• The upper side of the root elongated faster than
the lower side of the root
• The root bend downwards

298. • When the root bend downward, the auxin
distribution becomes equal on all side
• The roots continue to grow straight downwards

299. • Auxin are also used to stimulate the growth of
adventitious roots from the stem
– Used to trigger the adventitious roots for commercial
plants

300. • Induce the development of fruit without
fertilisation or parthenocarpy
• Parthenocarpy is used to produce seedles fruits

303. Ethylene
- a plant hormone which is synthesised during the
ripening of the fruit
- synthesised in – fruits, leaves, stem
- in the form of gas

304. - functions :
- speeds up the ripening of fruits
- stimulating the production of cellulase
- cellulase hydrolyses the cellulose in plants
making it soft

305. - promotes the breakdown of complex
carbohydrates into simple sugar
- make fruits taste sweet

306. • Placing a basket of ripe mangoes with unripe
bananas can induce ripening of banana